possible bug in tcp_probe
Hi, I'm using linux v2.6.22.6 and tcp_probe with a couple of small modifications[1]. Even with moderately large numbers of flows (16 on the one machine) and increasingly as I monitor more flows than that, I get strange overflow problems such as this one: 74.259589763 192.168.2.1 36988 192.168.3.5 5001 0x679c23dc 0x679bc3b4 18 13 9114624 78 76 1 0 64 74.260590660 192.168.2.1 44261 192.168.3.5 5006 0x573bb3ed 0x573b700d 13 9 5254144 155 127 1 0 64 74.261607478 192.168.2.1 44261 192.168.3.5 5006 0x588.066586741 192.168.2.1 33739 192.168.3.5 5009 0xe26d1767 0xe26cf577 2 3 13090816 443 15818 1 0 64 88.066690797 192.168.2.1 33739 192.168.3.5 5009 0xe26d1767 0xe26cfb1f 3 3 13092864 2365 15818 1 0 64 88.067625714 192.168.2.1 59385 192.168.3.5 5012 0x411c1090 0x411bd258 12 9 14578688 2807 15812 1 0 64 As you can see the third line has been truncated as well as the next roughly 14 seconds of data after which data continues writing as usual. I don't think my small changes are causing this but perhaps I'm wrong. Does anyone know what might be causing the above? Many thanks for any ideas, Gavin [1] I have slightly modified tcp_probe to print out information for a range of ports (instead of one port or all) and to print info from the congestion avoidance inet_csk_ca struct. This adds a couple of extra fields to the end. If either of these are of interest as patches I'll happily submit them. - To unsubscribe from this list: send the line unsubscribe netdev in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: possible bug in tcp_probe
Hi. On Tue, Nov 13, 2007 at 11:26:15AM +, Gavin McCullagh ([EMAIL PROTECTED]) wrote: 74.259589763 192.168.2.1 36988 192.168.3.5 5001 0x679c23dc 0x679bc3b4 18 13 9114624 78 76 1 0 64 74.260590660 192.168.2.1 44261 192.168.3.5 5006 0x573bb3ed 0x573b700d 13 9 5254144 155 127 1 0 64 74.261607478 192.168.2.1 44261 192.168.3.5 5006 0x588.066586741 192.168.2.1 33739 192.168.3.5 5009 0xe26d1767 0xe26cf577 2 3 13090816 443 15818 1 0 64 88.066690797 192.168.2.1 33739 192.168.3.5 5009 0xe26d1767 0xe26cfb1f 3 3 13092864 2365 15818 1 0 64 88.067625714 192.168.2.1 59385 192.168.3.5 5012 0x411c1090 0x411bd258 12 9 14578688 2807 15812 1 0 64 As you can see the third line has been truncated as well as the next roughly 14 seconds of data after which data continues writing as usual. I don't think my small changes are causing this but perhaps I'm wrong. Does anyone know what might be causing the above? Log buffer has limited size, you can not write from different threads to it and expect all data being printed synchronously, there is nothing exceptional here. -- Evgeniy Polyakov - To unsubscribe from this list: send the line unsubscribe netdev in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: possible bug in tcp_probe
Gavin McCullagh [EMAIL PROTECTED] writes: I'm using linux v2.6.22.6 and tcp_probe with a couple of small modifications[1]. Even with moderately large numbers of flows (16 on the one machine) and increasingly as I monitor more flows than that, I get strange overflow problems such as this one: You probably just need to increase the buffer (bufsize option to the module or tcp_probe.bufsize if compiled in) In general I think tcp_probe was always more intended a demo of how kprobes could be used than a real production tool (with no offense to sch) -Andi - To unsubscribe from this list: send the line unsubscribe netdev in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: possible bug in tcp_probe
Hi Gavin, This is fixed in the current version of tcp_probe by Stephen. Please see the below. commit 662ad4f8efd3ba2ed710d36003f968b500e6f123 Author: Stephen Hemminger [EMAIL PROTECTED] Date: Wed Jul 11 19:43:52 2007 -0700 [TCP]: tcp probe wraparound handling and other changes Switch from formatting messages in probe routine and copying with kfifo, to using a small circular queue of information and formatting on read. This avoids wraparound issues with kfifo, and saves one copy. Also make sure to state correct license, rather than copying off some other driver I started with. Signed-off-by: Stephen Hemminger [EMAIL PROTECTED] Signed-off-by: David S. Miller [EMAIL PROTECTED] You can copy the current version of tcp_probe to your kernel version and it should work. Before this has not been fixed, in my case, I changed kfifo not to put the data if it doesn't have enough space. I will send you a patch if you want this. Regards, Sangtae On Nov 13, 2007 6:26 AM, Gavin McCullagh [EMAIL PROTECTED] wrote: Hi, I'm using linux v2.6.22.6 and tcp_probe with a couple of small modifications[1]. Even with moderately large numbers of flows (16 on the one machine) and increasingly as I monitor more flows than that, I get strange overflow problems such as this one: 74.259589763 192.168.2.1 36988 192.168.3.5 5001 0x679c23dc 0x679bc3b4 18 13 9114624 78 76 1 0 64 74.260590660 192.168.2.1 44261 192.168.3.5 5006 0x573bb3ed 0x573b700d 13 9 5254144 155 127 1 0 64 74.261607478 192.168.2.1 44261 192.168.3.5 5006 0x588.066586741 192.168.2.1 33739 192.168.3.5 5009 0xe26d1767 0xe26cf577 2 3 13090816 443 15818 1 0 64 88.066690797 192.168.2.1 33739 192.168.3.5 5009 0xe26d1767 0xe26cfb1f 3 3 13092864 2365 15818 1 0 64 88.067625714 192.168.2.1 59385 192.168.3.5 5012 0x411c1090 0x411bd258 12 9 14578688 2807 15812 1 0 64 As you can see the third line has been truncated as well as the next roughly 14 seconds of data after which data continues writing as usual. I don't think my small changes are causing this but perhaps I'm wrong. Does anyone know what might be causing the above? Many thanks for any ideas, Gavin [1] I have slightly modified tcp_probe to print out information for a range of ports (instead of one port or all) and to print info from the congestion avoidance inet_csk_ca struct. This adds a couple of extra fields to the end. If either of these are of interest as patches I'll happily submit them. - To unsubscribe from this list: send the line unsubscribe netdev in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line unsubscribe netdev in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: possible bug in tcp_probe
Hi Sangtae, On Tue, 13 Nov 2007, SANGTAE HA wrote: This is fixed in the current version of tcp_probe by Stephen. Please see the below. You can copy the current version of tcp_probe to your kernel version and it should work. Many thanks, I'll give this a try, Gavin - To unsubscribe from this list: send the line unsubscribe netdev in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
